About the best defense against these wee buggers is floating row covers. Trap crops, plants they prefer over the ones your prefer, can also help if planted some distance away. The dusts and sprays often recommended, Carbaryls, Malathion, Spinosad, Neem Oil, etc. to control these wee buggers are very broad spectrum poisons that will not only also harm any beneficial insects that might aid in control but also those insects necessary for pollination of these plants.

I read that Spinosad is not very effective against flea beatles...I just purchased some for the use of caterpillars, so if it helps with the flea beetles too I'll be super delighted!